1. Field of the Invention
The present invention relates to a video reproduction apparatus and a video reproduction method, and in particular to a video reproduction apparatus and a video reproduction method for, when a video bit stream having a compressed video signal, such as an MPEG video signal, recorded therein is input and expanded to decode the compressed video signal into an original video signal, displaying information regarding a bit rate of the video bit stream.
2. Description of the Related Art
FIG. 4 is a block diagram of a conventional video reproduction apparatus 400. The video reproduction apparatus 400 reproduces a video signal based on a video bit stream including a plurality of pictures and having a picture type of each of the plurality of pictures recorded therein.
In this specification, the term “picture type” refers to a type of inter-motion compensation frame encoding in an MPEG video encoding system as is well known, and can be one of three picture types of I picture (intra-coded picture), P picture (predictive coded picture) and B picture (bidirectionally-predictive coded picture). In general, a number of bits per picture is largest in the I picture, second largest in the P picture, and smallest in the B picture (I picture>P picture>B picture).
The video reproduction apparatus 400 includes a video decoder 41 for receiving and expanding a video bit stream and thus outputting a video signal, a picture start point detection circuit 42 for receiving the video bit stream and detecting a picture start point which represents a start point of each of a plurality of pictures included in the video bit stream, and a frame count circuit 43 for counting a number of times that the picture start point detection circuit 42 detects the picture start point and measuring a predetermined time unit. The video reproduction apparatus 400 also includes a bit rate calculation circuit 44 for counting a number of bits included in each of the pictures in the video bit stream for the predetermined time unit and outputting the counted number of bits as an average bit rate, and a video signal generation circuit 45 for receiving the output from the bit rate calculation circuit 44 and generating a bit rate video signal for displaying the average bit rate. The video reproduction apparatus 400 further includes a video signal addition circuit 46 for adding the video signal output from the video decoder 41 and the bit rate video signal output from the video signal generation circuit 45, an NTSC conversion circuit 47 for converting the video signal obtained by the video signal addition circuit 46 into a video signal of an NTSC format, and a D/A conversion circuit 48 for converting the output from the NTSC conversion circuit 47 into an analog signal.
The video reproduction apparatus 400 having the above-described structure operates as follows.
The video decoder 41 receives and expands a video bit stream, and thus outputs a video signal. The picture start point detection circuit 42 receives the video bit stream and detects a picture start point which represents a start point of each of a plurality of pictures. The frame count circuit 43 counts a number of times that the picture start point detection circuit 42 detects the picture start point and measures a predetermined time unit. The bit rate calculation circuit 44 counts a number of bits included in each of the pictures in the video bit stream while the frame count circuit 43 measures the predetermined time unit, and outputs the counted number of bits as an average bit rate. The video signal generation circuit 45 receives the output from the bit rate calculation circuit 44 and generates a bit rate video signal for displaying the average bit rate. The video signal addition circuit 46 adds the video signal output from the video decoder 41 and the bit rate video signal output from the video signal generation circuit 45. The NTSC conversion circuit 47 converts the video signal obtained by the video signal addition circuit 46 into a video signal of an NTSC format. The D/A conversion circuit 48 converts the output from the NTSC conversion circuit 47 into an analog signal.
In a conventional video reproduction apparatus, while a moving picture including a plurality of pictures is being reproduced, the average bit rate representing the total of the number of bits included in a plurality of pictures per time unit is displayed. However, while a still picture is being reproduced, the average bit rate relating to the plurality of pictures is not displayed since display of such an average bit rate is meaningless.
A reproduction apparatus is now demanded which, even while a still picture is being reproduced in, for example, a pause mode or in a frame-by-frame reproduction mode, can display information relating to the bit rate, such as the picture type or the number of bits of the picture corresponding to the still picture.